package sanshui.system.trade.util;

import lombok.Data;
import org.springframework.stereotype.Component;
import sanshui.system.trade.db.mapper.TradeDataTblMapper;

import javax.annotation.Resource;

@Data
@Component
public class IdWorkerUtil {

    @Resource
    TradeDataTblMapper tradeDataTblMapper;

    public interface IdType{
        public static final String ACCOUNT_ID = "ACCOUNT_ID";
        public static final String WORKER_ID = "WORKER_ID";
        public static final String REPORT_ID = "REPORT_ID";
        public static final String LIMIT_ID = "LIMIT_ID";
        public static final String OPERATION_ID = "OPERATION_ID";
    }

    public synchronized Long nowId(String idType){
        switch (idType){
            case IdType.ACCOUNT_ID:
                return tradeDataTblMapper.accNowId();
            case IdType.WORKER_ID:
                return tradeDataTblMapper.workerNowId();
            case IdType.REPORT_ID:
                return tradeDataTblMapper.reportNowId();
            case IdType.OPERATION_ID:
                return tradeDataTblMapper.opNowId();
            case IdType.LIMIT_ID:
                return tradeDataTblMapper.limitNowId();
        }
        throw new RuntimeException("生成自增ID失败, ID_TYPE:" + idType);
    }

    //下面两个每个5位，加起来就是10位的工作机器id
    private long workerId = 1;    //工作id
    private long datacenterId = 1;   //数据id
    //12位的序列号
    private long sequence;


    //初始时间戳
    private long twepoch = 1288834974657L;

    //长度为5位
    private long workerIdBits = 5L;
    private long datacenterIdBits = 5L;
    //最大值
    private long maxWorkerId = -1L ^ (-1L << workerIdBits);
    private long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
    //序列号id长度
    private long sequenceBits = 12L;
    //序列号最大值
    private long sequenceMask = -1L ^ (-1L << sequenceBits);

    //工作id需要左移的位数，12位
    private long workerIdShift = sequenceBits;
    //数据id需要左移位数 12+5=17位
    private long datacenterIdShift = sequenceBits + workerIdBits;
    //时间戳需要左移位数 12+5+5=22位
    private long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;

    //上次时间戳，初始值为负数
    private long lastTimestamp = -1L;

    public long getWorkerId() {
        return workerId;
    }

    public long getDatacenterId() {
        return datacenterId;
    }

    public long getTimestamp() {
        return System.currentTimeMillis();
    }
    public int getIntTimestamp() {
        String time = Long.valueOf(System.currentTimeMillis()).toString();
        return Integer.parseInt(time.substring(time.length() - 6, time.length()));
    }

    //下一个ID生成算法
    public synchronized Long nextId() {
        long timestamp = timeGen();

        //获取当前时间戳如果小于上次时间戳，则表示时间戳获取出现异常
        if (timestamp < lastTimestamp) {
            System.err.printf("clock is moving backwards.  Rejecting requests until %d.", lastTimestamp);
            throw new RuntimeException(String.format("Clock moved backwards.  Refusing to generate id for %d milliseconds",
                    lastTimestamp - timestamp));
        }

        //获取当前时间戳如果等于上次时间戳（同一毫秒内），则在序列号加一；否则序列号赋值为0，从0开始。
        if (lastTimestamp == timestamp) {
            sequence = (sequence + 1) & sequenceMask;
            if (sequence == 0) {
                timestamp = tilNextMillis(lastTimestamp);
            }
        } else {
            sequence = 0;
        }

        //将上次时间戳值刷新
        lastTimestamp = timestamp;

        /**
         * 返回结果：
         * (timestamp - twepoch) << timestampLeftShift) 表示将时间戳减去初始时间戳，再左移相应位数
         * (datacenterId << datacenterIdShift) 表示将数据id左移相应位数
         * (workerId << workerIdShift) 表示将工作id左移相应位数
         * | 是按位或运算符，例如：x | y，只有当x，y都为0的时候结果才为0，其它情况结果都为1。
         * 因为个部分只有相应位上的值有意义，其它位上都是0，所以将各部分的值进行 | 运算就能得到最终拼接好的id
         */
        return ((timestamp - twepoch) << timestampLeftShift) |
                (datacenterId << datacenterIdShift) |
                (workerId << workerIdShift) |
                sequence;
    }

    //获取时间戳，并与上次时间戳比较
    private long tilNextMillis(long lastTimestamp) {
        long timestamp = timeGen();
        while (timestamp <= lastTimestamp) {
            timestamp = timeGen();
        }
        return timestamp;
    }

    //获取系统时间戳
    private long timeGen() {
        return System.currentTimeMillis();
    }


}